1. Field of the Invention
The invention relates to walking beam conveyors for moving elongated pieces of materials and particularly to a walking beam type of cooling bed in which heated round bars are moved along fixed, notched beams by reciprocating notched beams. More particularly, the invention relates to an improved drive mechanism for the reciprocating beams which in addition to advancing the bars along the fixed beams and rotating them 90.degree. will rotate the bars 90.degree. in their respective notches without advancing them.
2. Description of the Prior Art
Walking beam types of conveyors have been used for many years for the transporting of materials such as billets, ingots, round and rectangularly shaped bars and the like for heating and cooling purposes. These walking beam conveyors consist of a plurality of fixed beams having notches formed therein in combination with a plurality of reciprocally movable notched beams which are interposed in-between the fixed beams.
A drive mechanism is connected to the moving beam and imparts various types of motions thereto depending upon the particular design and function of the conveyor for advancing the heated or cooled material. The materials are located each in a respective notch and move successively along the notches of the fixed beam until they are discharged at one end thereof. In a cooling bed application the material generally is cooled by ambient air as the material moves along the cooling bed. Other of these walking beam conveyors when used for heating purposes transfer material through a heating chamber or furnace. Certain of these known cooling beds will turn or rotate the material as it is advanced along successive notches to prevent bending of the material due to its heated state.
Some examples of these prior art walking beam conveyors, many of which are used for either heating or cooling of material, are shown in U.S. Pat. Nos. 3,003,615, 3,128,651, 3,332,539, 3,417,858, 3,462,004, 3,648,827, 3,744,620, 3,746,146, 4,040,514, 4,102,449 and 4,135,704. These known walking beam conveyors use a variety of mechanisms for connecting a drive means with the movable notched beam. Certain of these prior conveyors use eccentrics and various cam arrangements for engaging and driving the movable beam. Still others use various bellcrank and other types of levers and connecting linkages for imparting this movement to the movable beam. Furthermore many of these prior constructions use a dual motion arrangement wherein the drive mechanism imparts both a vertical and horizontal motion to the beam which results in a circular-type motion thereto for picking up the material from its particular notch and depositing it in the adjacent notch toward the discharge end of the conveyor.
One shortcoming of these known walking beam conveyors is that the drive mechanism of the movable beam is relatively complicated and expensive due to the multiple drive shafts and connecting linkages to the movable beam. As discussed above, these walking beam conveyors, in addition to advancing the materials along the cooling bed between the deposit and discharge ends, also will rotate the material to prevent the material from bending or drooping downwardly due to the heated state of the material. If the material was transferred along a cooling bed without rotation, the ends and unsupported intermediate areas of the material would deform due to the weight thereof.
This material deformation becomes an extremely serious problem when the movement of the material longitudinally along the conveyor is stopped for any reason, such as a problem at the discharge end due to an excessive accumulation of discharged materials or some type of malfunction or equipment breakdown.
Thus, the need has existed for a walking beam conveyor and in particular for such a conveyor that is used as a cooling bed which has a single drive shaft and associated drive mechanism for reciprocating the moving beam to move the material longitudinally along the fixed beams and which also enables the material to be rotated within their respective notches without advancement along the bed. There is no known cooling bed construction of which we are aware which achieves these advantages.